Road building machine



ROAD BUILDING MACHINE Filed Nov. 21; 1935 5 Sheets-Sheet 1 t I 41 Iawe/WM;

"7 J. N- HELTZE} Jane 16, 1940. J. N. HELTZEL ROAD BUILDING MACHINEFiled Nov. 21, 1935 5 Sheets-Sheet 3 2E gwucwlo J. N. HELTZ BL Fl 1;. 5.z

Jan, 16, 1940.

J. N. HELTZEL ROAD BUILDING MACHINE Filed Nov. 21, 1935 5 Sheets-Sheet 4awe/whom:

J- NHBLTZ 16, 1940. I J, TZ 2,187,080

" ROAD BUILDING MACHINE Filed Nov. 21, 19:55 S'Sheets-Sheet 5 oiJNHBLTZg Patented Jan. 16, 1940 UNITED STATES PATET OFFiCE 6 Claims.

The present invention relates to improvements in road building machinesand is a continuation.

in part of my prior application for Road making machines, Serial No.475,492 filed August 15, 1930.

An object of the present invention is to provide an improved method anddevice for producing curb formations at the edges of a concrete roadadjacent the side forms.

Another object of the invention is to produce a raised central portionin the road in and about the zone of the joint to reinforce andstrengthen the material at the sides of the joint and the road slabswhereby to avoid spalling off of the lastic material.

A further object of the invention is to provide an improved form ofscreed and method of hanging or suspending the same whereby the screed,in addition to operating in its normal transversely reciprocatingmanner, may be given a rocking motion on its suspension whereby tocompact the concrete in a novel way.

It is a still further object of the invention to produce an improvedscreed or finishing implement capable of forming lip curbs.

A still further object of the invention is to pro-v duce an improvedscreed or finishing implement for the purpose of preventinghoney-combing of the concrete at the sides of the road-adjacent the sideforms by compacting the concrete downwardly to fill up such voids aswould otherwise be rearward movements of the implement and also uponlateral reciprocating movements of such implement; to provide guards forthe sides of the machine to prevent the loose aggregate from spillingover the side forms; to provide detachable devices at either of thesides and/or in the center of the screed for producing compactingeffects upon the concrete at the sides and center portions of the slabs.

With the foregoing andother objects in view, the invention will be morefully described hereinafter, and will be more particularly pointed outin the claims appended hereto.

In the drawings, wherein like symbols refer to like or correspondingparts throughout the several view,

Figure 1 is a perspective viewof a road building machine constructed inaccordance with the present invention.

Figure; 2 is a fragmentary perspective view, with parts broken away andvparts shown in section, and illustrating the central arched constructionof the screed.

Figure 3 is also a fragmentary perspective view showing the finishedform of slab.

Figure i is also a perspective view with parts of the roadway and sideforms shown in section, illustrating a modified form of road buildingmachine.

Figure 5 is a similar View showing a modified form of screed-and guardplate.

Figure 5-A is a cross-section taken on the line I ii-A -5 --A of Figure5.

Figure 6 is also a perspective View with portions of theroadway shown insection and the side forms broken away, illustrating the same "form ofscreed with guard plates at the front and rear of the same.

Figure '7 is a similar View showing a modified form of screed in whichthe compacting devices are detachable.

Figure 8 is a similar View showing the com-- pacting member in place.

Figure 9 is a perspective View of a. part of the compacting memberseparated from the screed, and

Figure 10 is a perspective view of a finishing machine having the novelfeatures of this invention applied thereto.

Referring more particularly to Figures 1, 2 and 3 of the drawings whichcorrespond to Figures 6, '7 and 8 of my-prior co-pending applicationSerial No. 475,492, platforms in are shown with reinforcing mesh llthereon. The platforms 3-0 are linked, as by'the chains or otherconnections ll, to the subgrader or other machineby which the same aredrawn along. The mesh 45 may be laid on the platforms it and, as thepouring-of the concrete progresses, the platform or platforms 40 aredrawn from under the mesh.

After the concrete'has been poured and the mesh reinforcing installed,the screed member 42 follows, which screeds off the concrete.

The screed is shown more particularly in Figure 2 and is composed ofdivided base plates t3 and 44 having the side angleircns 45 and it,between which are arranged the braces til. The. base plates #3 and 44are separated and indented, as indicated at 48; and the angle bars arearched upwardly at a central point between the two base plates, asindicated at 19. At 5!) is shown the screeding bar which encounters theconcrete, this bar resting upon the base plates #33 and it and againstthe vertical web of angle irons 46.

The recessed and arched screed will supply a surplus of material in thecenter of the road along the joint blade 39. In both Figures 1 and 2 Ithe raised central portion of the concrete is indicated at 5|, thisraised portion being formed as the screed passes over the concrete.

The screed member 42 follows progressively back of the pouring. Thisscreed member will preferably be a mechanically-operated screed havingan eccentric, as hereinafter described, for reciprocating the screedtransversely of the roadway.

The screed has the arched portion 48 as heretofore referred to. Thisarched portion may be completely closed on the bottom face so as toprevent arry material from projecting through the screed, or it may beprovided with the opening 48 which will permit surplus mortar to projectthrough the screed to be deposited in the rear of the screed, asindicated at 5!. The screed has adjusting screws to vary the archedportion 9. There is an offset a: at either or both ends of the screed toproduce a header or curb r-l along the edge of the road.

In Figure 2, I have shown more "fully the opening in the screed,together with the arched mem bers. The rear member 55 of the screed maybe raised slightly more than the front member It will be understood thatthe front member will depress the stone or coarse aggregate below thesurface and the finer material will accumulate in the open space ill. Asthe screed moves forward, the finer material will project in the rear ofthe screed, as shown at E5.

The open space 48 may be provided with sides or braces ll t retain thesurplus material within the space 48. The joint forming member or jointmaterial 39 is shown in place after the joint installing operation hasbeen completed. This elevated joint 5i will eliminate the low jointswhich have been experienced from time to time where the plain or regularsurface type of screeds have been used. The recess in the screed may beVaried by adding filler plates M secured by bolts or suitable fasteningmeans 49 In Figure 3, I have shown a slab of concrete molded as it wouldappear in complete form. The raised portion of the slab '52 along thelongitudinal joint is indicated at El. It will be understood that thisraised screed member may be used in connection with any type oflongitudinal joint forming a raised portion to guide traffic and preventsurface water entering the joint.

It is desirable in many instances to form a curb or header, such asindicated at w-! in Figure i, sometimes at both sides of the road, andin other cases only on one side of the road. This curb is sometimescalled a lip curb.

The object of forming the curb by the screed member 22 is to providemeans whereby the concrete contained in the curb or header is builtintegrally with the base portion of the roadway. This is accomplished byoffsetting the lower face of the screed as indicated at It will beunderstood that the screed is reciprocated transversely in theconventional way well known in the art. After the concrete header orcurb has been formed by the reciprocating screed, suitable temporaryforms may be positioned to support the concrete curb until the concretehas hardened sufficiently; thereafter, the forms may be removed. Theforms referred to are of a type well known in the art.

It will be understood that the screed 42 reciprocates transversely inthe conventional manner and is pushed forward progressively with themovement of the conventional finishing machine to which my improvedscreed may be attached.

Referring more particularly to Figure i, there is shown a method offorming what is generally termed lip" curbing, as indicated at Xl-A bythe use of the laterally-reciprocated screed member I. This screed maybe carried forwardly and backwardly by the conventional finishingmachine. This screed is provided with depressed portions ii at oppositesides of the raised center. The screed rests on the side forms 2 and isarched upwardly, as indicated at 3 to the contour of the lip curb |A.The distance between the arched or upwardly curved ends 3 of the screedis less than the distance between the lip curbs at opposite sides of theroad to give the screed an opportunity to reciprocate laterally acrossthe road without destroying the lip curbing and to better compact thesame.

Also the arched central portion M: of the screed is struck on a greaterradius of curvature than the resultant raised central portion 5! of theroadway, the reciprocating action of the screed compacting the materialat opposite sides of the joint.

Either mechanical or electrical vibrating devices l may be provided onthe screed to vibrate the screed as the screed is reciprocated andpushed forward to strike off the concrete level with the tops of theforms 2 and simultaneously build up the lip curbing.

The machine is arranged for forward and backward screeding. The screedmember may rest on the side forms 2 for back screeding, and I" tosimultaneously form the lip curb with the backward movement of themachine in the same way as it would in the forward movement of suchmachine.

A longitudinal joint cutting blade 5 may be positioned under the screedas shown more particularly in my prior Patent No. 1,982,337, granted.November 27, 1934. The joint cutting blade is provided with slots '1 topermit up and down movement of the blade when the screed is raised outof position by the lifting chains or other suitable devices 8. Suchlifting members 8 are provided on each side of the screed and arecarried up to the frame of the machine, being wrapped or Wound aroundthe pipe member or shaft 9, which is secured to the frame of the machinein the conventional manner.

By rotating the pipe member or shaft 9, the screed may be raised andlowered with respect to the surface of the roadway. It has been found tobe very practical to raise the screed approximately six inches above theside forms when making the first strike oil of the concrete, and whilethe screed is thus elevated to reciprocate the same by use of the armit] and eccentric H or other means, such eccentric being operated by asuitable power unit carried by the machine.

The vibrators 4 may also be operated to vibrate the screed during theoperation of the initial strike-off of the material.

It is very important at this stage of the operation to understand that,when the screed is suspended on the chains 8 and reciprocated laterallyby the eccentric H, the screed will swing on an are having a radius withpivot point at 9.

Such screed motion will produce a tainping action on the concrete, andin this way the screed will serve as a tamping member, as well as ascreeding member.

Iii]

By operating the screed in the various manners above described therewill result a maximum amount of compaction to the concrete. Therefore, avery dry concrete may be used.

Modern specifications require transverse con traction joint. Such ajoint is indicated at It. A transverse joint may be produced by theblade member l3 positioned adjacent the front of the screed. The loweredge of the blade is out to the contour of the lip curb. The blade is issupported and movable up and down, by the screw members M or otherdevices, the same being manipulated by the hand wheels 55.

It will be understood that, when cutting the transverse joints 12, theforward movement of the machine is stopped and the ends of the screedrest on the side forms 2. The screed may be reciprocated laterally andalso vibrated by the vibrators 4 as the blade I3 is moved downwardlyinto the concrete by the hand wheels it: and screw members 44. It may bedesirable in some cases not to reciprocate the screed when cutting thetransverse joints. Instead, the joint may be produced by moving theblade 63 down into the concrete progressively while the screed isvibrated by the vibrators 4.

In practice it has been found that forms are not required for supportingthe lip curb, as indicated at XIA, because of the fact that the curb isof a rather flat construction. However, when curbs are produced with avertical face. as indicated in Figure 1, it is necessary insuch cases tosupport the face of the curb by suitable form members which arepositioned back of the screed after the curb material has been formed ormoved up into position.

Referringmore particularly to Figure this figure illustrates amodification of screed construction wherein a reciprocating screed isprovided with a fiat base portion it. Such flat portion rests on top ofthe side forms 2 on both sides of the roadway. The bottom portion itconstitutes a wide surface and may be arched to conform to the requiredcrown of the roadway; thus, the bottom portion it of the screed mayperform the function of producing the finished surface of the concrete.

It has been found in practice in building concrete roads thathoneycombing or voiding has not been overcome by the conventional designof screeds heretofore used. It has been necessary, therefore, forworkmen to spade the concrete along the side fonms; however regardlessof the spading of the concrete along the side forms, this voiding orhoneycombing along the inside face of the forms has never been overcome,but it has compelled engineers to provide a thickened edge adjacent theside forms. I have overcome the necessity of hand spading along the edgeof the forms by providing upwardly-flared walls I6A at the forwardportion of the screed, and similar upwardly-flared walls iii- B at therear edge portion of the screed. These upwardlyfiared walls terminateinwardly from the ends of the screed at points designated generally atl6C, which may be approximately six to twelve inches inside of the sideforms. When the screed is moved forward against the accumulation or bodyof loose concrete, the upturned wall lB-A will form a. raised portionalong the side forms; in other words, an excess amount of concrete willbe positioned along the side forms. The volume of this material will becontrolled by the height of the flare i6.-A. As the screed movesforward, and is reciprocatedthe bottom surfacing portion US of thescreed forces this excess material downwardly level with the top treadsof the side forms 2. The walls lfi-A and Iii-B flare or incline not onlyin a forward and rearward direction but also transversely of the roadwaydownwardly to the terminal points l6-C whereby these shoulders ortransversely inclined or rounded end parts itC thrust the excessmaterial laterally toward the side forms and in a downward direction asindicated by the arrow in Figure 5. This has the eifect to pack theconcrete against the vertical face 2A of the side form 2.

. The flared or inclined walls ltA and lt-l3 are not carriedcontinuously. across the front or rear faces of the screed, and thesewalls may or may not be integral with the screed. Separate wallstructures are shown in connection with subsequent figures of thedrawings.

The screed i6 is reciprocated transversely of the roadway and is poweredfor backward and forward screeding, for instance in the manner shown anddescribed in my co-p-ending application Serial No. 369,475 filed October25, 1932. Owing to this backward and forward movement, the front andrear parts of the screed carry the flaring or inclined walls.

In the forward motion of the screed, the front flared walls l6-Avirtually forms a raised curb. This curb portion is then forced down andcompacted by the flat surfacing portion it of the screed. On the rearmovement of the screed the opposed flared wall Iii-B has a similareffect.

After the necessary material has been forced down against the sideforms, perhaps there may not be any surplus coarse aggregate with whichto contend. When this stage of the operation is reached. the surface ofthe concrete is then considered to be completely finished, and all ofthe coarse aggregate that could possibly be forced down along the sideform-s has already been projected in position, so that, in effect, anarmoured edge along the roadway is produced by the compaction of anexcessive volume of coarse aggregate longitudinally along the zone ofthe side forms.

To prevent the coarse aggregate from rolling over the side forms, one ormore baffle plates or guards I! are provided. Such baffle plate may besupported by members it secured to the carriage of the machine. Slots l9in the members 18 admit of the vertical adjustment of the baffle plate;while slots 25! which intersect the. vertical slots 19 are useful toallow the baffle plate I! a longitudinal play within the limits of thehorizontally elongated slots 21!. Bolts or other fastenings 6 passthrough the intersecting slots to bind the baffle plates 9? to thesupports H3 in the adjusted position. The two adjustments permit thebaffle plate to be moved toward and. from the rear vertical face 2! ofthe screed and also allow the lower edge of the bafiie plate I! to belifted and lowered with respect to the top tread of the side form 2.

Referring more particularly to Figure 5---A, this figure is across-section taken on the line 5A5A in Figure 5. The section looks inthe direction of the arrow and shows the other end portion of the screedwith the flared end wall sections.

Referring more particularly tov Figure 6, this figure shows morecomprehensively the screed and the guard plates of Figures 5 and 5--A.The front vertical face of the screed is indicated at 2|, and the rearvertical face by a like number.

The flared walls lG-A and lt-B are shown at v both ends of the screed.These walls function during both the forward and rear passes of thescreed. The excess concrete to be thrust down against the inside facesof the side forms is indicated at 22. In this case two baffle plates I?are provided. One baffle plate is arranged forwardly of the screed atthe side of the roadway, and a second baflle plate follows the screed insubstantial alinement with the front bafile. One or more baille platesmay also be mounted at the right hand end of the screed. The bafileplates may be arranged with their lower edges very close to the treadsof the side forms, in which case they will prevent any excess materialflowing over the top of the side forms. However, the openingsimmediately under the flared walls will permit excess moisture or waterto drain off of the surface of the roadway over the tops of the formsand between the bafile plate N. This is desirable because excess mortar,moisture or water are apt to produce a scaling effect on the surface ofthe roadway. Therefore, to prevent this scaling of the surface of theroadway provision is made to drain this excess water or moisture fromthe surface to the roadway by permitting the water to drain under theflared walls l6-A and l6B.

The screed is reciprocated by the arm l driven by the eccentric l l,which is driven from any suitable source of power preferably installedupon the carriage or bridge. This carriage or bridge may be of aconventional type. A vibrator 4 is shown in this instance as beingmounted centrally of the screed. One or more vibrators may be mounted atdesired positions along the length of the screed. Such vibrator may beeither mechanically or electrically operated for the purpose ofvibrating the screed as the screed reciprocates transversely and moveseither forwardly or rearwardly over the roadway.

Now the segregation of concrete is corrected by the forward and backwardmovement of the screed. In Figure 6 a transverse windrow 23 of coarsematerial is shown. This material has been carried backwardly in thedirection of the arrows by the screed during its backward movement andwhile being reciprocated in contact with the road material. Thisbackward screeding eliminates the necessity of workmen shoveling therequired material back to a rearward point which has been the commonpractice. Backward screeding also serves to thrust the coarse aggregatein a back direction, as well as in a forward direction, and will alsothrust the excess material against the side forms during the backwardmovement, as well as during the forward movement. This forward andbackward screeding method has been described in my prior applicationabove referred to Serial No. 369,475. Before the final forward pass ofthe finishing machine is made. the machine will be backed up to a pointas indicated at X-Z in Figure 6, and the screed lowered in positionwhereby, when the screed moves forward it will reciprocate on thesurface of the roadway and pick up the excess material from the windrow23, carrying such excess material forwardly. The operation is repeatedprogressively throughout the length of the roadway. The finished roadwayis indicated at 24 in Figure 8 and includes the installation of thejoints l2.

In cases when an armored surface is desired throughout the entiresurface of the road, to provide a harder wearing surface a sufficientquantity of coarse stone or aggregatepreferably dry-may be added byspreading a layer of such coarse stone or aggregate over the surface ofthe roadway after the concrete has received its initial screeding. Suchlayer of stone or coarse aggregate may be quite uniformly spread byworkmen with shovels.

After this layer of coarse aggregate or stone has been spread over thesurface of the roadway, the machine is then moved over the roadway withthe screed reciprocating and simultaneously vibrated progressively asthe machine moves over the roadway.

The thrust member IE will engage the stone or coarse aggregate, whichhas been spread substantially uniformly over the surface of the greenconcrete and, consequently, thrust down into the plastic concretetherebyabsorbing the surplus moisture and causing the mortar to be thrustaround the stone or coarse aggregate and thereby thoroughly coating thecoarse material by the combination screeding and vibrating process andattracting sufficient mortar to the surface to completely cover thestone or coarse aggregate and provide a smooth surface finish with thecourse of stone reposing very close to the top surface of the finishedslab to provide a dense or armored surface devoid of surplusmortarthereby preventing the scaling or peeling off of the top surfaceof the concrete. The armored surface produced by this method willprolong the life of the roadway by minimizing the abrasion action of thetraffic on the surface of the road because of the fact that the toplayer of stone serves as an armored surface, which will greatly prolongthe life of the road.

Referring more particularly to Figure 7, there is herein shown amodified form of the screed involving the use of removable flared wallmembers which may be attached to the front or to the rear walls, orboth, of the screed. These removable wall members are for packing thematerial along the side forms 2. Furthermore a central packing membermay be aflixed to the central part of the screed at the front or at therear, or both, for the purpose of packing the road material along thecenter joint.

The object of this device is to prevent the formation of voids orhoneycombing as indicated at 26 along the side forms. This honeycombingor voiding is particularly to be noted when the side forms have deformedvertical faces as shown at A. The flared wall member at the left end ofthe screed has been removed. The wall of the screed is provided withhorizontally elongated openings 29 adapted to mate with verticallyelongated slots 28 to receive bolts or other fastening means forsecuring the wall member 21 to the screed. The wall member is designatedgenerally at 21 and is formed with a vertical web or flange 30 and ahorizontal web or flange 3|. The slots 28 are produced in the verticalweb 30, which vertical web is adapted to be placed against either thefront or rear wall of the screed.

The removable member 2'1 carries a baffle plate HA to prevent the coarsematerial from being projected over the top of the side form. Such memberl'l--A is positioned so as to perform the function of preventing thestone or coarse aggregate from rolling over the side forms; however, thesmall arched portion |'lB will permit surplus water to drain off overthe side forms. This arched portion HB will be of such dimensions as toprevent the coarse stone from moving therethrough.

The horizontal flange 3| is formed with a flared or inclined wall I6Ehaving end wall sections IB-F which incline not only rearwardly as does7 the wall section l5-E but also flare downwardly until the same mergewith the horizontal flange 3|. The wall section i6-E thrusts thematerialdownwardly and the end wall sections l6-F tend to converge the materialto the central wall section ld- E whereby the material is compacteddownwardly progressively as the screed is moved forward. The end wallsection l6F, owing to their transverse inclination, will also force thematerial downwardly as the screed is reciprocated by the eccentric H andarm ID. This compacting of the concrete downwardly causes the same tofill out against the side forms thus preventing the formation of voidsand honeycombing.

On the opposite end of the screed there is shown a modified form ofremovable wall member, which is not provided with a baifie plate butwhich contains the inclined wall sections Iii-E and l6F. The outer wallsection l6F is omitted and this device is so mounted that it bridgesover the tread of the side form 2.

In the central portion of the screed is a central detachable member 32which is in most respects similar to the left endmember in that it isadjustably secured in substantially the same manner and is formed withthe central inclined wall iii-E and the two inclined end wall sectionsl5-F made in the lower horizontal flange. This member is not providedwith any side baflie plate. The central member is positioned in thecenter of the screed whereby the wall section l8-E will pack thematerial on one side of a division plate D, which is sometimes used inroad construction. Inorder to prevent honeycombing, this plate ifdeformed, requires an excessive amount of hand spading. It will beunderstood that by the use of the attachment 32 such member 32 willthrust coarse material down along the plate D and compact it to preventhoneycombing along the plate throughout the length of the roadway. Itmay be desirable to attach thrust members ifi to the screed so as tomore thoroughly compact the concrete through the entire width of theroad.

The edges of the roadway, as well as the middle. are considered the twoWeakest points in modern roads. Therefore it is important that theefficiency of the road at these points he increased to the maximum. Inorder to tie the road slabs together, dowel bars as indicated at B, areused at spaced intervals longitudinally of the road. Associated with thedowel bars are load transfer plates L. These plates have anchor elementsM which project back into the slab to hold these plates securely inposition. Therefore, the dowel bar B will bear against the shear platesL through which the bars pass and will transfer the load from one slabto the other and will prevent the concrete from shattering due toexcessive loading.

Referring now to Figure 8 this figure shows at the left hand end of thescreed a device similar to that shown at the right hand end in Figure 6.

The recessed portion beneath the inclined walls lE-E and l6 F actuallyforms a curb O, representing comparatively loose, coarse material, whichis progressively compacted by the shoulder or wall Hi -E and. by theshoulder or wall section i'F. This curb O is thrust down along the sideforms and compacted substantially by the entire weight of the screed andfinished with the bottom face it of the screed.

Rigid requirements for high strength concrete now being demanded callfor further radical improvements in vibrating apparatus. Therefore, inaddition to surface vibration as described herein, I propose to attachto the finishing machine an internal vibrated apparatus, which willvibrate the concrete internally prior to the screeding operation, aswell as immediately after the preliminary screeding of the concrete. Thestrength of concrete is greatly depreciated because of the air pocketsor minute bubbles as they might be called being trapped in the plasticmass.

In order to dispose of these minute air pockets in the plastic concrete,I provide an internal means of vibration, which may be attached to theconventional finishing machine, of which 35 is the frame of saidmachine; 36 represents the screed of the finishing machine, which may beof the conventional type or of the improved type illustrated in thisapplication. The screed rests on the side forms 37 and is reciprocatedin the conventional manner.

The internal vibrating apparatus comprises frame members 248, which arepivoted to the finishing machine at 3 3. The frame is provided withwheels 33, which operate on the side forms 37!. These wheels 33 areprovided with rubber tires so as to prevent the vibrations being carriedto the side forms.

There is a vertical housing '52 at each side .of the frame. Thetransverse frames 53 are supported by the housings. The frames '53 arecushioned by the spring members 5d. The transverse shaft 55 is supportedby the transverse frames 53. There are a series of rotary members 56supported by the shaft in a rotating position. These members 56 areprovided with a series of prongs "5?, which are secured to the rotarymembers 56, which are preferably made of tubular sections. These membersto rotate by gravity progressively by the forward movement of themachine by projecting these pins down into the plastic concrete to thedesired depth. Their contact within the plastic concrete will producethe desired rotary movement of these vibrating elements in and out ofthe plastic concrete progressively as the machine moves forward.

The shaft 55 and the members 56 are supported immediate of the housings52 by a series of die frames or brackets 58, which are secured to thetransverse members 53 and project down and engage the rotating members56.

When operating the machine, the concrete is placed on the subgrade ofthe road and is struck off to the desired height above the side forms bythe strike-off member 553, which is arranged to be adjusted up and downto and from the concrete by the hand wheels fill and the screw members6!.

As the machine moves forward, the concrete is struck off to the desiredheight and the pins or elements 5? are moved down into the plasticconcrete to desired depth and progressively as the machine moves forwardvibrations are produced on the beam members 53 by the mechanicalvibrators 62, which are actuated by the universal shaft 553, power beingtransmitted from a suitable power unit positioned on the finishingmachine, or if desired, these vibrators may be operated electrically.

It will be understood that a large number of vibrating elements 5?penetrate the plastic concrete and are vibrated progressively as themachine moves forward and these elements pierce the plastic concrete,and as the shaft rotates, the elements are withdrawn from the plasticconcrete progressively as the machine moves forward. Therefore,substantially all of the air pockets are punctured so the air may bereleased from the mass of material.

The vibrating elements 51 are pointed at their ends so as to prevent thepossibility of depressing any of the coarse aggregate. It is veryimportant that the coarse aggregate remains closely to the top surfaceof the concrete. Therefore, these vibrating elements are pointed toprevent any possibility of thrusting any of the coarse aggregatedownwardly.

Immediately back of the internal vibrating element is positioned ascreed member 36, which reciprocates progressively as the machine movesforward so that the compaction of the concrete by the screed ismaterially assisted because of the internal vibration of the concreteimmediately forwardly of the screed.

In order to induce maximum compaction and assist in the surfacing ofvery dry concrete, a sufficient number of vibrating elements 64 aresupported on the vibrated frame 53 with the spring members 65 tofacilitate the required vibration on the screed by the mechanicalmethod.

It will be understood that electrical vibrators may be used in lieu ofthe mechanical vibrators as illustrated.

It will be understood that the vibrators may remain in position whenscreeding forwardly or backwardly. Therefore, the concrete may betreated by vibration both forwardly or backwardly as may be desired.

It is important to note that in the construction of concrete roads,involving the use of reinforcing mesh as indicated at 66, the bottomcourse of concrete 6! is first positioned and struck off to the properelevation by the strikeoif plate 59 and during the forward movement ofthe machine-while the bottom course is being struck off, the vibratingelements are moved down into the plastic concrete by the hand wheels 68and the threaded screws 69 or by some other suitable means.

After the bottom course has been struck off and vibrated, the mesh 66 isthen laid and the top course of concrete I is placed and struck off tothe proper elevation by the strike-off plate 59. The machine is thenmoved forward with the vibrating elements moved down into the plasticconcrete. The vibrating elements will vibrate the concrete massinternally.

The vibrating elements 57 will more or less contact the reinforcing 66so that the vibrators will cause vibrations to be carried throughout thereinforcing, as well as throughout the mass of concrete.

It is understood that the strike-off member 59 may also be used forcutting and installing transverse contraction joints if desired.

A longitudinal joint H may be produced by suitable joint cutting element13. This element may consist of a substantially flat bar as shown, whichis secured to the frame 53, and is arranged for up and down adjustmentby the screw and hand wheel 8|A. The member 13 may be moved down so asto contact the reinforcing steel 66 so that the member 13 will vibratethe steel reinforcing.

I have found that by placing a plurality of bars 13 to the frame 53 ithas been found practical to vibrate concrete when used in connectionwith grids. I have found by this method very uniform vibrations can besupplied to grids and very stiff concrete can be effectively vibratedinto the grids for bridge decks, railroad crossings and the like.

When using this apparatus in connection with the installation of grids,the vibrating elements 51 are moved down into the pockets of the steelgrids, thereby vibrating the concrete internally and providing means forejecting the air. When the grids are simultaneously vibrated by theplurality of bar members 73, it has been found that concrete having noslump whatever is effectively compacted and voiding is entirelyeliminated.

It will be understood that this joint cutter is simultaneously vibratedbecause of its contact with the frame 53.

It is obvious that various changes and modifications may be made in thedetails of construction and design of the above specifically describedembodiment of this invention without departing from the spirit thereof,such changes and modifications being restricted only by the scope of thefollowing claims.

What is claimed is:

1. In a road building machine, a screed, means to reciprocate thescreed, said screed having upwardly-arched central and end bottomportions, a transverse joint forming blade carried to move andreciprocate with the screed and having upwardly-arched central and endbottom edge portions, and means to move the blade up and down withrespect to the screed.

2. In a road building machine, a reciprocating surfacing member, meansfor moving said surfacing member backwards or forwards, and wallscarried by the forward and rear portions of the member, said walls beingat the end portion of the member only and being flared upwardly inopposite directions from the base of the member, the walls also flaringtoward the central part of the member and toward the plane of theworking surface of said member.

3. In a road building machine, a forwardly movable and laterallyreciprocating surfacing member having inclined longitudinal walls at theend portions only extending over the treads of the side forms and for ashort distance inwardly of such side forms and a shield member followingthe surfacing member and adjustably supported with respect to the rearportion of said surfacing member and to the treads of the side forms.

4. In a road building machine, a surfacing member, means to move themember backwards and forwards, means to reciprocate the memberlaterally, said member having forward and rear inclined walls at the endportions only thereof for straddling the side forms and extendinginwardly for a distance therefrom, said walls being flared forwardly andlaterally, shields carried forwardly and rearwardly in close relation tothe end portion of said surfacing member, and means to adjust saidshields with relation to the treads of the side forms and the adjacentend portions of the surfacing member.

5. In a road building machine, a screed, means to reciprocate thescreed, said screed having upwardly-arched end bottom portions, atransverse joint forming blade carried to move and reciprocate with thescreed and having upwardlyarched end bottom edge portions, and means tomove the blade up and down with respect to the screed.

6. In a road building machine, a screed having an upwardly-arched endbottom portion to form a curb along the edge of the roadwaysimultaneously with the formation and surfacing of the plastic materialof the roadway, a transverse joint forming blade also having anupwardly-arched end bottom portion, means for adjustably supporting saidblade from said screed,

means for reciprocating the screed and blade transversely of theroadway, and vibrating means on the screed above the upwardly-arched endbottom portion for vibrating the screed and the cutter simultaneouslywith the screed from a point above the curb.

JOHN N. HELTZEL.

